Insulating material.



UNITED STATES arana GEORGE H. RUPLEY, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL COMPANY, A CORPORATION OF NEW YORK.

INSULATING F MATERIAL.

. Specification 01' Letters Patent.

Patented Nov. 24. mos.

Application flied August 7, 1907. we 1%. 987,000.

To all whom it may concern:

Be it known that I, GEORGE H. RUPLEY, ,a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Insulating Material, of which the following is a specification. This invention relates to a process for treating fabrics for electrical uses and has for its object the production of a fabric which will be eflicient as an insulating covering for coils and the like and which may be produced in a cheap and simple manner.

The present practice in the insulating of coils, such for instance dynamo-electric machines, is to wind the coils with a fabric and then .coat the fabric with varnish. This varnish is then hardened, as for instance by baking, and another coating of varnish is ap lied. These operations are continued until the desired insulation of the material is obtained. In the carrying out of this process it first takes several coatin s sometimes as many as three or more to fill up the pores of the fabric and the remaining coats are then available as an insulating la er. I have found that this process can e greatly sim lified and the cost of the same reduced by illing the ores 'of the fabric before it is varnished. T is is preferably done before the fabric is applied to the coil. The pro erties of the filler must be such as to ren er the fabric flexible so that it canbereadily applied to the coil and stretched in place. The material must also be such that it -will not be destroyed by the baking process. The material should have the properties of rubber; that is, something that is soft and pliable for a long time after the impregnation but will be preferably non-adheslve. Ordinary rubber cannot be used since it will be destroyed by the temperature used in baking the varnish.

In the carrying out of my invention I take a fabric, which ma be a cheap grade of cloth, cut it into wide strips, and apply a filler or sizing of some rubber-like substance. I have found that ve etable itch which has some properties of ruiber wi I serve the purpose. I have also found a very valuable material in combining75 parts of vegetable oil, such as linseed oil, with 25 parts of being forced into the pores or as field coils for hydrocarbon black. These materials are boiled together with suitable driers, such as zinc oxid, until it reaches a sta in which it is as solid as can be and still capable of applied by means of a solvent as by painting it on to the fabricql It may then be applied to the fabric by immersing the cloth in it or by means of calender rolls. Afterthe i'mpre ation, the fabric will be baked or not as i und desirable. I have found that by impregnating the cloth with this material that it will remain flexible and can thus be applied in a very efficient manner; that is, at can be drawn taut and stretched around corners and irregular places. Itcan also be torn in strips so as to form talr andnoselvage edge is necessary. The clo ith'us impre atedis wound on the coil and a coating 0 varnish is then ap lied ner as by aking.

I have found that with an unimpregnated fabric six coats of varnish are necessary, while three coats with a baking after each coating will serve the same pur ose with an impregnated fabric. saving in the cost of production as well as in the saving of time since-each varnishing operation must-be followed by a drying and a baking 0 eration. The essentials of the filled cloth somewhat yielding and also inoxidizable beyond the flexible state. It is preferable that the cloth shall not he adhesive as would be the case with ordinary rubber or adhesive ta e, and to prevent adhesion I coat with ta 0 or similar materials.

It will be understood, of course, that while I have'desoribed s e-cifid materials whereby my invention may e carried out, these materials are merely typical and may be varied as may also the manner of applying the same without departing from the spirit of my in vention, the scope of which is set forth in the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is, 1. Aninsulating material "for electrical purposes comprising a fabric impregnated with an elastic heat resistance material and coated with a baked varnish. 2. An insulating material for electrlcal purposes comprising a fabric impregnated ELEormc This resu ts in a great are that it shall be flexible and and hardened in some manu with an elastic non-adhesive material and with a soft pliable non-adhesive material coated with abaked varnish. and coated 'wlth 'linseed oil varnish. 10 3. An insulating material for electrical In witness whereof, I have hereunto set purposes comprising a fabric impregnated my hand this 3rd da of Au st, 1907. 5 with an elastic non-adhesive heat resistance GEdl'lGE RUPLEY.

material and coated with a baked varnish. Witnessesi 4. An insulating material for electrical BENJAMIN B. HULL,

purposes comprising a fabric impregnated HELEN 0mm). 

